Tag Archives: Virginia geology

It has been a long wait for spring this year. What a winter! Naked Mountain had lots of snow and impeded my progress a number of times. One time, my car got completely stuck at the very bottom of my road. I loaded three days of fresh groceries into my backpack and hiked the two and a half miles up to the house in the snow. It was tiring, but I was pleased with myself that I could do it without too much trouble at the age of 66!

But now comes the reward – spring! I ventured out onto the summit to look for spring ephemerals. I didn’t have to go very far; they were everywhere! In peak bloom were acres of Bloodroot (Sanguinaria canadensis) and Cut-leaved Toothwort (Dentaria lacinata).

Bloodroot (Sanguinaria canadensis) blooming on Naked Mountain.

Cut-leaved Toothwort (Dentaria laciniata) blooming on Naked Mountain.

Here is a photo of a lovely blooming patch of Trailing Arbutus (Epigaea ripens). This is not technically on Naked Mountain, but rather on the banks of Dutch Creek which flows at the Northeastern base of Naked Mountain. It offers a fragrant welcome to all who make the sharp left turn up my road.

I also checked out the progress of a small colony of Shooting Stars (Primula meadia) on the edge of a small barren on the ridge top near the house and was surprised to see how many were popping up. Six years ago there were only two plants, now there are 16. So, this colony is beginning to take off. Naked Mountain is unusual for its massive quantities of Shooting Stars numbering at least ten thousand.

Shooting Stars (Primulus meadia) emerging on Naked Mountain.

I stumble on colonies in various places on the mountain and have been watching the progress of this one near the house. The soil seems to favor their growth as it has a mafic substrate, specifically amphibolite, which has been metamorphosed from basalt. So, the soil has higher concentrations of calcium and magnesium, similar to limestone, which is where Shooting Stars are more frequently found. According to samples collected by Natural Heritage Program staff, it also happens to have lower concentrations of iron compared to most soils on mafic substrates. I discussed this with Gary Fleming, senior vegetation ecologist with the Virginia Natural Heritage Program (DCR) who posits that since Shooting Stars are a prairie flower, the pathways to its distribution East in Virginia are limited by the barrier of the Blue Ridge Mountains. Shooting Stars must have the right alkaline soils, lower elevations, both of which describe Naked Mountain, and access to a prairie pathway.

How about that railway in the valley at the base of the Southeastern slope of Naked Mountain? Maybe, but it goes South, not West. So, a delightful mystery!

The shock part of the meeting was presented by the first speaker, a geologist (of course!), at the Virginia Native Plant Society’s annual workshop held on March 16th at the University of Richmond. The general topic was, “Piedmont: Places and Plants.” The geologist, Dr. Callan Bentley, Assistant Professor of Geology at Northern Virginia Community College, discussed, “Geologic Roadkill: The Deep History of Virginia’s Piedmont.” In one short, fascinating hour he described the evolution of the Earth, basically billions of years of plate tectonics, or continental colliding and rifting, and how this activity is manifested in the rocks and soils that make up the Piedmont we see today. You can see a map and geologic information about the Virginia Piedmont here.

About two-thirds of the way through his lecture Dr. Bentley showed a slide depicting fault lines that underlie the Piedmont, particularly one that runs right under the North Anna Nuclear Plant in Louisa County! A Wikipedia search notes, as did Dr. Bentley, that although informed in 1977 of the fault by consulting geologists, Dominion (the power company that owns the site) went ahead and built the entire plant right on the fault line and then lied about it to the public. Their argument to scientists raising concerns was that the Nuclear Regulatory Commission had assessed there had not been an earthquake in the area for probably thousands of years. This was followed up in 2010 by an NRC report which estimated the risk each year of an earthquake intense enough to cause core damage to the reactor at North Anna at 1 in 22,727.

Those of us who live in Virgnia know what happened next. On August 23, 2011 a 5.8 magnitude earthquake occurred in Mineral, Virginia a mere 11 miles from the North Anna Nuclear Plant. The plant lost power and shut down for over three months. It suffered cracks to several buildings and on-site spent-nuclear-fuel long term storage canisters shifted. Dominion denies any of this damage compromised safety. In fact — right now — Dominion is planning to expand the plant’s facilities.

It was a little hard to focus on the rest of Dr. Bentley’s talk — especially for those in the audience who live near the North Anna Nuclear Plant!

Smooth Coneflower — USDA Photo

The hope part of the meeting was offered by the last speaker, Dr. Ryan Klopf, Mountain Region Steward for the Virginia Department of Conservation and Recreation’s Division of Natural Heritage, and the steward for the Naked Mountain Natural Area Preserve – my home. Dr. Klopf’s topic was, “Piedmont Community and Ecosystem Restoration.” He began by providing a history of the ecology of the Virginia Piedmont. During the Hypsithermal period, which occurred for several thousand years beginning around 10,000 years ago, North America experienced an unusual, extended period of drought which caused a lot of fires. During this time, prairie and savanna plant species spread eastward from the great plains of the Mid-West. From 4,000 BCE until the Europeans arrived in the 16th century, the Piedmont of Virginia was characterized by open canopies of oaks, hickories and pines. The understories were a rich herbaceous layer of at least 277 different species. As the climate changed and became more temperate with increased moisture, the prairies and savannas were maintained, ecologists believe, through regular burning by Native Americans. It is surmised that this was done to help these early Americans hunt and travel. When Europeans arrived, they altered this landscape significantly through their agricultural practices, reducing Piedmont prairies to the sunny edges of farmed fields and naturally dry places that inhibit tree growth. Reforestration of much of the Eastern United States over the past century has also pushed out these prairie and savanna species.

For more than a decade, the Division of Natural Heritage has been invested in restoring the ecology for these disappearing prairies species. The Division has employed a process of prescribed burning in several of the state’s Natural Area Preserves where these species were found in remnant communities. Dr. Klopf presented the findings for two of these sites, Difficult Creek NAP and Grassy Hill NAP. At Difficult Creek in Halifax County, an area of 819 acres that contains hardpan forest, remnants of prairie, and an underlying mafic geology that supports species diversity, Heritage Division stewards resolved to replace a loblolly pine plantation on the site with historic Piedmont savannah species. Using prescribed fire, tree thinning and invasive species management, the effort has produced a very positive outcome: Oaks have increased from 11 percent to 27 percent; hickories 8 percent to 25 percent; native grasses have increased from 16 percent to 28 percent and the native herb layer has increased from just 0.5 percent to 9 percent. One example from the latter statistic, Smooth Coneflower (Echinacea laevigata),has increased from 211 plants in 2002 to 866 plants in 2008.

At Grassy Hill Natural Area Preserve in Franklin County a similar effort has had comparable results. The native grassland herbaceous layer is reassembling including increased presence of Andropogon viginicus, also known as Broomsedge, and Parthenium auriculatum, or Wild Quinine.

In between the shock and the hope lectures, two other presenters, Christopher Ludwig, chief biologist with the Virginia Department of Conservation and Recreation’s Division of Natural Heritage and co-author of the newly published Flora of Virginia, and Dr. Tim Spira, professor of botany at Clemson University rewarded the rapt audience with eye candy – beautiful slides of endemic wildflowers of the Piedmont and their dwelling places and pollinators.

You can learn more about the Virginia Native Plant Society, the sponsor of this excellent workshop, and its many other programs and benefits for the native plant lover here.